Abstract: Objective To investigate the expression of serum miR-222-3p, human epididymal protein 4 (HE4) and carbohydrate antigen 125 (CA125) in epithelial ovarian cancer (EOC) and its clinical significance. Methods A total of 118 EOC patients, 105 in the benign group and 60 in the healthy control group were selected in our hospital. The expression of serum miR-222-3p was detected by real-time quantitative PCR, and the levels of HE4 and CA125 were detected by chemiluminescence. The diagnostic value of serum miR-222-3p, HE4 and CA125 levels to EOC were analyzed by ROC curve. Pearson correlation analysis showed that the expression of miR-222-3p in EOC patients was correlated with HE4 and CA125. Results The levels of serum miR-222-3p (1.62±0.74 vs 0.84±0.35, 0.73±0.24), HE4 (346.20±58.72 pmol/L vs 53.46±11.63 pmol/L, 48.60±9.75 pmol/L) and CA125 (307.60±94.25 U/mL vs 26.83±11.56 U/mL, 20.72± 9.40 U/mL) in EOC group were significantly higher than those in benign group and control group (P<0.001). ROC curve showed that the best cutoff values of serum miR-222-3p, HE4 and CA 125 were 1.16, 187.50 pmol/L and 162.80 U/mL, respectively. The area under the curve (0.948, 95% CI: 0.887~0.995) of the three combined diagnosis of EOC was the largest, and its sensitivity and specificity were 96.8% and 89.5%. Correlation analysis showed that the expression of miR-222-3p in EOC patients were positively correlated with HE4 and CA125（r=0.847,P<0.001,r=0.793,P<0.001）. Conclusion The levels of serum miR222-3p, HE4 and CA125 were significantly increased in EOC patients, and the three combined tests were of high value in the diagnosis of EOC.

Key words: Epithelial ovarian cancer, MiR-222-3p, Human epididymal protein 4, Carbohydrate antigen 125